Sheet metal box



P 3, 1947. E. T. TURNEY, JR 2,427,823

SHEET METAL BOX Filed March 26, 1945 INVENTOR. f'aaw- 7.7224 5; (7%

Patented Sept. 23, 1947 UNITED STATES PATENT OFFICE SHEET METAL Box Eugene T. Turney, Jr., Bayside, N. Y.

Application March 26, 1945', Serial No. 584,882

3 Claims.

The invention herein disclosed relates to boxes and particularly such as are used for enclosing and protecting transformers and other electrical parts.

Boxes of this nature must be water-tight and must be strong enough to stand rough treatment and to maintain their water-tight condition under unusual conditions, such as dropping or other rough handling.

Objects of the invention are to provide a box of simple, inexpensive form, easy to assemble and in. which the parts when put together will be; automatically interlocked and become securely fastened together. and which, further, in the assembled and interlocked relation will provide the means for completing the necessary sealed joints between the. parts.

Other desirable objects and the novel features by which the purposes of the invention are attained will appear or are set forthin the course of the following specification.

The drawing accompanying and forming part of the specification illustrates a present commercial embodiment of the invention. Structure, however, may be modified: and changed as regards the present illustration, all within the true intentv and broad scope of the invention as hereinafter defined and claimed.

Fig. 1 in the drawing is a perspective View of a transformer box incorporating and embodying the invention;

Fig.2 is an enlargedand'. part sectional View as on substantially the plane of line 22 of Fig. 1;

Fig. 3 is a similar View on substantially the plane of line 33 of Fig. 2.

In the form of the box illustrated, the side wall structure 5 is made up of a single continuous piece of sheet metal bent at the corners to provide the four-sided box outline and having the ends lapped and secured at one corner, as by brazing, soldering or welding, as indicated at 5.

The ends 1 of this box body are constructed as shown in Figs. 2 and 3, with a dependent edge flange 8 bent substantially at a right angle to the general plane of the piece and adapted to snugly slide in over the inner faces on the side wall panels of the box body.

These edge flanges are utilized as part of the means for mechanically securing the ends in place. For this purpose they are shown as provided with part spherical, inwardly struck lugs 9, partially severed along the lines of maximum displacement to leave the abrupt inwardly oiiset cut edges I0.

The. balance of the mechanical securing means isprovi'ded, in the illustration, by locking strips H of sheet metal, welded at !2 or otherwise suitably secured over the inner face of the side wall, at some distance inward from the open ends and having inwardly offset free portions 13 extending toward the open ends and slotted at M to provide openings for receiving the lugs 9 and abrupt edges IE to overstand and interlock with the abrupt shoulders or edges ID of the lugs.

Fig. 3 shows how the offset at 16 locates the free portions of the holding strips inwardly of the end flanges and gives these portions a spring character enabling them to yield to the pressure of the inwardly displaced lugs as the ends are pushed into seated position.

To avoid the possibility of pushing the ends too far into the box body, the outer edges I! of the strips are disposed to form stops engageable with'the under sides of the ends, as in Fig. 3; to locate and hold such ends in definitely fixed relation-, with the cooperating edges l0 and I5 of the holding lugs and edge flanges interlocked and securing the parts in that relation.

The inward offset of the free portions of the securing strips also provides free space for entry of; the edge flanges into the end of the box body. To further facilitate this action and avoid the possibility of the edges of the strips momentarily interfering with entry of the end flanges, the outermost edges of the strips may be inclined inwardly as indicated at Hi, to serve as beveled guides for theentering flanges and as wedge faces which will facilitate entry of the inwardly displaced lugs 9.

The entire rim portions of the box ends are shown as indented at I9 inwardly of the edge flanges, to form with the side wall, when the ends are in place, the roove 0r trough for the solder or other sealing medium 20. As shown in Fig. 3, this indentation may be on a bevel or incline substantially matching the incline l8 of the outer edges of the securing strips, so that in the final position the free portions of the securing strips will not be forced inwardly or held away from their securing engagement with the lugs of the flanges,

In the construction illustrated, the interlocking securing means are provided only at two opposite sides of the box, but it will be apparent that such means may be provided at all four sides or at any lesser number of sides, depending on the size of box, the weight and mass of the contained transformer windings, etc. Also, while in Fig. 2 only two unit locks, that is lugs and perforations, are shown, it will be evident that any number of these may be provided, spaced and otherwise disposed to carry the necessary load and provide the required security.

In practice the securing strip is usually rolled to the approximate cross section shown and punched with regularly spaced perforations, and such strip is then cut in any lengths required for the boxes in which it is to be used. To give this strip a desired degree of initial stifiness the edge which is innermost of the box may be flanged more or less substantially as indicated at 2|.

The invention provides a means by which the box ends may be quickly and accurately located in the box bodies. Once thus located they are firmly and positively held and cannot be pushed inward in the soldering or other sealing operations.

The securing strips reenforce and strengthen the side wall, and the ends when interlocked as disclosed reenforce and. are reenforced by the side wall. The structure thus is strong and of a permanent nature, mechanical strains being taken by the securing means instead of by the soldered connections. The latter assures that the box will continue in water-tight condition even though subjected to heavy strain. The invention is adapted to plain imperforate box ends such as shown in Fig. 1, or to ends which may be otherwise shaped, perforated or formed to suit special needs or requirements.

What is claimed is:

1. A box comprising a sheet metal side wall, a cooperating sheet metal end having an edge flange to slide in over the inner face of the side wall, said flange having a partially severed and inwardly struck lug, and a locking strip secured over the inner face of the side Wall at a point inwardly of the entered flange of the end and having a free projecting portion overlapping the flange and perforated in line with and interlockingly receiving said inwardly projected severed edge portion of the lug, said end being indented, at the juncture of the flange therewith to form in conjunction with the end portion of the side wall a trough for sealing medium and whereby said box may be sealed water-tight and air-tight after locking the end in position as described.

2. A box comprising a sheet metal side wall, a cooperating sheet metal end having an edge flange to slide in over the inner face of the side wall, said flange having a partially severed and inwardly struck lug, and a locking strip secured over the inner face of the side wall at a point inwardly of the entered flange of the end and having a, free projecting portion overlapping the flange and perforated in line with and interlockingly receiving said inwardly projected severed edge portion of the lug, said end being indented, at the juncture of the flange therewith to form in conjunction with the end portion of the side wall a trough for sealing medium, the end of said free portion being disposed for engagement by the inner face of the box end to serve as a stop for positioning the inserted box end and to predetermine the depth of the sealing medium trough about the edge of said box end.

3. A box comprising a sheet metal side wall, a cooperating sheet metal end having an edge flange to slide in over the inner face of the side wall, said flange having a partially severed and inwardly struck lug, and a. locking strip secured over the inner face of the side wall at a point inwardly of the entered flange of the end and having a free projecting portion overlapping the flange and perforated in line with and interlockingly receiving said inwardly projected severed edge portion of the lug, the edge of said free projecting portion being inclined inwardly on a bevel to serve as a guide for the entering edge of the flange and said box end being indented at the juncture of the flange therewith to form in conjunction with the side wall a trough for sealing medium, said inward inclination of the edge of said locking strip aifording space for accommodation of said inward indentation of the box end.

EUGENE T. TURNEY, JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,368,052 Powell Feb. 8, 1921 1,105,143 Johnson July 28, 1914 2,332,299 Cohn Oct. 19, 1943 564,060 Draper July 14, 1896 1,132,925 Gillette Mar. 23, 1915 1,160,611 Hudson Nov. 16, 1915 2,146,988 Roach et a] Apr. 23, 1937 FOREIGN PATENTS Number Country Date 28,902 Denmark Nov. 23, 1921 228,406 Germany Nov. 10, 1910 

